Anions play a pivotal role in biological, chemical and environmental processes, and they have begun to receive increased attention. Among anions, iodide is of special note not only because of its physiological importance in controlling metabolic activities but also as an essential factor in energy conversion processes. Both deficiency and excess of iodide can result in malfunction and disorders in the human body. In addition to its environmental and biological importance, iodide is a key component of a redox couple often used in solar-energy-harvesting systems. Various methods can be used for the determination of iodide, including photoluminescence, colorimetric detection, time-resolved absorption techniques, mass spectrometry, chromatography, Raman scattering and electrochemical profiling. However, because of its large size and weakly basic nature, the binding capacity of iodide is the weakest among the halide ions. Therefore, the development of a simple, rapid, direct and economical method for the determination of iodide is still under investigation.
Researchers have recently demonstrated high interest in the development of photoluminescence-based methods for the highly sensitive, rapid and selective determination of iodide. However, the complex preparation of the fluorophores, their low hydrophilicity, and the fact that the multistep determination of iodide usually involves a toxic reagent (Hg) has hampered the widespread application of photoluminescence-based methods.